I was over the moon to be able to capture the comet Jacques (C/2014 E2). On Friday night, I had clear skies, but couldn't see the comet, even with binoculars. Knowing that the comet was close to the constellation Cassiopeia in the north eastern sky, I pointed the 200mm lens in that direction.
To my surprise, there was a faint green dot amonst all the stars. So I added the 2x converter to give me a bit more reach. I now had 2x the 200mm = 400mm on a Canon 60Da which is a crop of 1.6 which was a total of 640mm. I exposed for 10 seconds [hense the star trails] at ISO 6400 with an aperture of f5.6. I was over the moon that the comet showed up so clearly.
Comet Jacques is the green object in the night sky. The green is caused by the contents of the comet melting as the comet is close to the sun.